It has already started. The first ripples from rising seas are inundating low-lying areas, threatening coasts and islands. Climate refugees around the world are fleeing regions beset by violent storms, extreme temperatures, melting glaciers, spreading deserts, swelling oceans and other escalating effects of global warming.

Billions of people are at risk and the number is growing. Environmental stress forced more than 25 million to migrate in 1998, according to a Red Cross and Red Crescent study—roughly the same number that fled armed conflict.

Even though specific events often cannot be pinned to global warming, the scientific evidence that climate change is radically remapping our planet forms a cumulative, consistent and alarming pattern. Everyone but the head-in-the-sand dolt and the hand-in-the-industry-pocket hack understands that as large areas of the planet become unsuitable for human life, the sad stream of climate refugees will become a torrent.

As a resident of the small South Pacific island of Tuvalu recently told NPR’s “Living on Earth,” a man needs only two skills: how to climb a coconut tree and how to catch a fish. On this remote atoll, halfway between Hawaii and Australia, where the land crests a few meters above the sea, the shoreline is visibly receding. Salt from rising tides is poisoning the palms; bleached and dying coral reefs no longer support the fish that support the people.

New Zealand, one of the few countries to acknowledge and plan for the coming flood of climate immigrants, has agreed to accept all 11,000 Tuvaluans, starting with a limited number each year. Many Tuvaluans live in Auckland, lonely and lost, without the support of community and culture, or the skills to survive an urban life based on money.

In much of South Asia, the irony of climate change is that it creates too little water in some places and too much in others. The summer runoff from mountain glaciers that now provides most of the drinking water to 40 percent of the world’s population is rapidly disappearing. And so are myriad inhabitants, forced to leave land their families tilled for generations.

In Bangladesh, refugees who can no longer farm on drowning coastal land are falling inward to cities already crammed with jobless and desperate masses. Smaller than Illinois, Bangladesh has 140 million people, almost half the U.S. population. Imagine what it will be like in 50 years, when the Bay of Bengal is predicted to cover 11 percent of Bangladesh’s land.

And then there is New Orleans. At a time when warming oceans fuel stronger storms, this below sea-level city in a hurricane-prone delta sits on sinking lands near a silt-clogged sea.

While the French Quarter parties once again, low-lying areas—which housed mostly African Americans and the poor—lie abandoned. Two years after Katrina, the richest country in the world leaves thousands of its climate refugees to live in poisoned trailers or camp in the kitchens of relatives far from their former homes.

Local and federal governments around the world seem paralyzed by callousness or a refusal to make hard choices. Should they spend billions to protect unsustainable, sometimes toxic land, with ever-stronger levees or pipe in water across hundreds of miles? Can they afford to permanently relocate endangered populations to affordable housing on less vulnerable, more valuable land?

And what about the self-indulgent fools society continues to subsidize—with insurance premiums, taxes or extraordinary and repeated rescues—who insist on building beach houses on eroding sand, mansions in fire-prone hills and sprawling ranches in the bone-dry desert?

Most officials have tallied the political and economic price of acting and have chosen to wring their hands and tread water.

In the days after the storm, some of Katrina’s exiles took umbrage at the label “refugee.” But they share much with displaced Bangladeshi and Tuvaluans half a globe away: poverty, powerlessness, and the misfortune of living under governments that are ill-equipped or disinclined to make hard choices. Driven from home, history and culture by a warming planet, they also share unofficial status as climate refugees—a category that no international treaties recognize or protect.

Individual countries and the United Nations need to develop policies to define and aid the casualties of dreadful energy policies and reckless consumption; they must expand treaties that protect political refugees to include those who flee the persecution of a deadly climate. And the industrialized countries that contributed most to the problem must contribute most to accepting and resettling climate refugees.

No one knows the winner in the race between the ravages of climate change and the meager but growing measures to mitigate it. But we already know who the losers are. From coral wreathed atolls in the South Pacific to the coast of Alaska, from sinking Bangladesh bearing the weight of impoverished millions, to the drowning city of New Orleans, the new climate refugees are flowing like tears.